Calcium carbonate decomposes when heated. The equation for the reaction is
CaCO3→CaO+CO2 \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 CaCO3→CaO+CO2Calculate the maximum mass of CaO\text{CaO}CaO that could be obtained when 250 tonnes of CaCO3\text{CaCO}_3CaCO3 is decomposed.
Give the unit.
[Mr of CaO=56;Mr of CaCO3=100;1 tonne=106 g][M_r \text{ of CaO} = 56; \quad M_r \text{ of CaCO}_3 = 100; \quad 1 \text{ tonne} = 10^6 \text{ g}][Mr of CaO=56;Mr of CaCO3=100;1 tonne=106 g]
mass of CaO = ______ unit ______
Calcium hydroxide, Ca(OH)2\text{Ca(OH)}_2Ca(OH)2, forms when water is added to calcium oxide. Give the chemical name of Ca(OH)2\text{Ca(OH)}_2Ca(OH)2.
Calcium hydroxide is often used to neutralise acidic soil.
A chemist neutralises 75.0 cm375.0 \text{ cm}^375.0 cm3 of 0.200 mol/dm30.200 \text{ mol/dm}^30.200 mol/dm3 hydrochloric acid with calcium hydroxide.
Ca(OH)2+2HCl→CaCl2+2H2O \text{Ca(OH)}_2 + 2\text{HCl} \rightarrow \text{CaCl}_2 + 2\text{H}_2\text{O} Ca(OH)2+2HCl→CaCl2+2H2OCalculate the amount, in moles, of HCl\text{HCl}HCl that is neutralised.
amount of HCl = ______ mol\text{mol}mol
Calculate the minimum mass, in grams, of Ca(OH)2\text{Ca(OH)}_2Ca(OH)2 required to neutralise the HCl\text{HCl}HCl.
[Mr of Ca(OH)2=74][M_r \text{ of Ca(OH)}_2 = 74][Mr of Ca(OH)2=74]
minimum mass of Ca(OH)2_22 = ______ g\text{g}g
A clear solution of calcium hydroxide, Ca(OH)2\text{Ca(OH)}_2Ca(OH)2, is made by dissolving calcium hydroxide in excess water. This solution is left exposed to air. The solution slowly goes milky as a faint white precipitate forms. Explain why a faint white precipitate forms.
80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.